Outline

Objective

The aim of this study was to assess whether the volume of the pontomesencephalic cistern in patients with unilateral facial pain is smaller on the affected side than on the healthy side and whether there is any difference in healthy volunteers.

Methods

In a prospective study, 40 patients (25: unilateral trigeminal neuralgia; 4: bilateral trigeminal neuralgia; 11: trigeminal neuropathy) and 17 volunteers underwent MR (1.5T, T2 TrueFisp 0.9 mm, coronal orientation). The volume of the surrounding cistern was measured along the course of the trigeminal nerve from its beginning at the pons to MeckelÂ´s cave and compared side by side according to the region of interest. The difference was also compared between patients and volunteers (t-test, p<0,05).

Results

In all patients with unilateral trigeminal neuralgia, the volume of the cistern was smaller on the affected side than on the healthy side. The difference between the healthy and affected side in patients with unilateral neuralgia was 13.1% (0-36,3%), in patients with bilateral neuralgia 0% (0-7%), in patients with neuropathy 5.6% (5,6-29,9%) and in volunteers 8.7% (0-29.1%). The difference between patients with unilateral neuralgia and volunteers and between patients with unilateral and bilateral neuralgia was significant (p<0.05).

Conclusions

In patients with unilateral trigeminal neuralgia, the pontomesencephalic cistern is smaller on the affected side than on the healthy side. Because adjacent nerves and vessels can trigger trigeminal neuralgia, it should be discussed whether such a relationship is caused by the smaller volume of the pontomesencephalic cistern on the affected side.